Substitution of calorie restriction for protective effects of estrogen on cardiometabolic risk factors and oxidative stress in obese postmenopausal rat model

Estrogen has an anti-obesity effect and plays an important role in improving cardiometabolic disorders. Weight loss and reduction in calorie intake impede the development of obesity-related cardiometabolic risk factors. Therefore, we investigated the substitution of calorie restriction for effects of estrogen on cardiometabolic risk factors and oxidative stress in obese postmenopausal rat model. In this study, adult female Wistar rats were allocated into Sham and ovariectomized (OVX) groups and were given standard diet (SD) or 60% high-fat diet (HFD) or 30% calorie restriction (CR) for 16 weeks, following this, animals received E2 (17-β estradiol; 1 mg/kg; i.p.) every four days for 4 weeks. Results showed that HFD elevated the body weight, BMI, food intake, and blood glucose (BG) level in both sham and OVX groups. In addition, HFD had negative effects on lipid profile and oxidative stress in these groups. Whereas CR decreased these indices in both Sham and OVX groups fed an HFD, it could not diminish the BG level in the OVX-HFD group. E2 treatment in OVX animals with or without CR reduced body weight, BMI, food intake, and BG level, and also had positive effects on lipid profile alterations and oxidative stress reduction. In comparison, no significant differences were observed regarding the effects of E2 with CR between two groups for body weight, lipid profile, BG, and oxidative stress in the OVX-HFD rats. Overall, CR prevents and ameliorates cardiometabolic risk factors induced by obesity in postmenopausal conditions and is also a good candidate for E2 substitution.